Many pet food companies have no longer want to talk about the use of Ethoxyquin. This was one the darling of the industry and very popular. It was defended as being a very safe preservative (antioxidant). This view has now been discarded after many settlement in litigation over its use and safety as a pet food preservative.
Ethoxyquin was formerly championed by many pet food manufacturers as being a very advanced and healthy addition to pet food. It was however never attempted to hide the fact that Ethoxyquin was never intended for use on a daily basis as in a pet food. The original start of Ethoxyquin was as (believe it or not) a rubber stabilizer and also as a color retention agent. This ensured that you car tires remained and your spices retained its colour.
Despite efforts by industry to have Ethoxyquin declared safe as a food stabilizing agent for human consumption, it is was only allowed for very limited applications and only with colored spices. There have been numerous stories of stillbirth, sudden liver failure, kidney dysfunction, permanent pigment changes, tumors and death thought to be caused by the addition of Ethoxyquin to pet foods starting in as early as 1987. After much of the problems food manufactures moved to safer Vitamin E and Vitamin c antioxidants. now I wonder why they never considered it int he first place. It was like reinventing the wheel for food preservatives.